In recent years there have been numerous proposals for passive vehicle occupant restraint belt systems, i.e., restraint belt systems which automatically transfer from a configuration in which a shoulder belt, a lap belt, or both a shoulder belt and a lap belt restrain the vehicle occupant, and a configuration in which they move out of the way of the occupant and allow him or her to enter or leave the vehicle. Usually the transfer of the system between restraint and release configurations is initiated when the vehicle door is opened and closed.
Many of the proposed systems have a moving anchor or a movable guide ring that slides along a guide rail located at the inside edge of the vehicle roof above the door, on the door panel or at an inboard location adjacent the seat. The moving anchor or movable guide ring is driven in some of the proposed systems by a wire that is sufficiently stiff to transmit motion in the pushing direction to the moving anchor or guide ring, but sufficiently flexible to enable it to bend along a non-linear path. Proper operation of such a drive wire ordinarily requires that the wire be enclosed within a casing and that the casing be secured adjacent the guide rail and at some other location fairly close to the drive motor or mechanical motion transmitter which drives the wire, thereby to constrain the drive wire for movement along a prescribed path of a prescribed length, as defined by the casing. A common type of drive wire is a so-called racked wire, which consists of a core wire and a helically wound tooth wire, that is driven by the output gear of a gear-reduced electric motor or a mechanical motion amplifier.
A number of requirements are imposed upon the casing and the drive wire to ensure effective, trouble-free operation of the drive system over the life of the vehicle. For one thing, the casing must be securely fastened so that it can endure thousands of cycles of operation of the system. The casing must also enable the movement of the drive wire through it as freely as possible in order to minimize the forces imposed on the wire, the motor or other drive device and the casing itself. The space within the casing should also be protected from intrusion of dirt and moisture that might damage the wire, such as by wearing, or interfere with the free movement of the wire through the casing. The devices for joining the casing to the guide rail and connecting up the system during final installation in the vehicle must take into account the practicalities of assembly line production techniques, which make it desirable that the system be capable of being installed as various subassemblies and then ultimately connected up at a convenient point in the assembly operation in a minimum of time. Inasmuch as the drive wire reciprocates back and forth within the casing and through the guide rail along the path that is partly curved and partly straight, the wire is subjected to repeated flexure, care must be taken that the guide wire is not subject to fatigue, particularly at some sort of splice or other type of connection that involves an abrupt transition between a comparatively flexible section and a comparatively rigid section where stress concentration may occur. Finally, the design of the system should take into account the possibility that it may be damaged and require repair or replacement of certain components. This possibility makes it desirable for there to be some way of readily disassembling the system in a manner that minimizes the number of components involved in the dissambly and also facilitates replacement of various components or subassemblies while leaving other components or subassemblies in place. Similarly, the reconnection of a repaired system should be provided for in a manner which can be easily accomplished with simple tools.
The inventor of the present invention has concurrently with the present invention proposed an improved connector for joining the casing of a drive wire to the end of a guide rail in a manner which is very simple to carry out, yet highly effective in producing a durable connection between the casing and the guide rail. That related invention is the subject of co-pending U.S. patent application Ser. No. 272,358, filed June 10, 1981 entitled "Connecting Member for Passive Seat Belt Systems" and corresponding Japanese Priority Utility Model Application No. 55-081831, filed June 13, 1980. The aforementioned invention makes no provision for retention of a lubricant in the casing and prevention of intrusion of lubricant into the guide rail, from where it might possibly reach other parts of the vehicle or the occupant's garments or otherwise become objectionable. Moreover, the lack of any confinement of the lubricant means that the lubricant will be lost over a period of time and will become less effective.
In the case of a system which utilizes a racked wire driven by an output gear of the drive device, it is highly desirable for the racked wire and gear to be lubricated for smooth running, minimum wear and consequent long life. Inasmuch as the racked wire moves back and forth to an extent equal to the distance along which the moving anchor or moving belt guide moves along the rail, it is inevitable that after only a few cycles of operation, the lubricant will move into and through the casing and ultimately be carried by the part of the drive wire that moves along the guide rail to the guide rail. Eventually, it is certainly possible that lubricant that reaches the guide rail will accumulate and at some time start dropping onto the floor or seat of the vehicle or perhaps flow along the moving anchor or guide and get on the belt. At the very least, the lubricant will contaminate the guide rail and diminish its appearance, particularly as dirt tends to accumulate by sticking to the lubricant. Exposure of a lubricant to the interior of the vehicle will inevitably result in the collection of dirt, particularly when the vehicle is operated in dusty conditions in dry climates. Contamination of the guide rail can lead to wear of the rail and the slider that moves along the rail and also can reduce the freedom with which the slider moves along the rail.